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1# SPDX-License-Identifier: GPL-2.0
2#
3# Building a vDSO image for AArch64.
4#
5# Author: Will Deacon <[email protected]>
6# Heavily based on the vDSO Makefiles for other archs.
7#
8
9# Include the generic Makefile to check the built vdso.
10include $(srctree)/lib/vdso/Makefile.include
11
12obj-vdso := vgettimeofday.o note.o sigreturn.o vgetrandom.o vgetrandom-chacha.o
13
14# Build rules
15targets := $(obj-vdso) vdso.so vdso.so.dbg
16obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
17
18btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
19
20# -Bsymbolic has been added for consistency with arm, the compat vDSO and
21# potential future proofing if we end up with internal calls to the exported
22# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
23# preparation in build-time C")).
24ldflags-y := -shared -soname=linux-vdso.so.1 \
25 -Bsymbolic --build-id=sha1 -n $(btildflags-y)
26
27ifdef CONFIG_LD_ORPHAN_WARN
28 ldflags-y += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
29endif
30
31ldflags-y += -T
32
33ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
34ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
35
36# -Wmissing-prototypes and -Wmissing-declarations are removed from
37# the CFLAGS to make possible to build the kernel with CONFIG_WERROR enabled.
38CC_FLAGS_REMOVE_VDSO := $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
39 $(RANDSTRUCT_CFLAGS) $(KSTACK_ERASE_CFLAGS) \
40 $(GCC_PLUGINS_CFLAGS) \
41 $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
42 -Wmissing-prototypes -Wmissing-declarations
43
44CC_FLAGS_ADD_VDSO := -O2 -mcmodel=tiny -fasynchronous-unwind-tables $(CONFIG_CC_OPT_INLINE_MEMSET)
45
46CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_REMOVE_VDSO)
47CFLAGS_REMOVE_vgetrandom.o = $(CC_FLAGS_REMOVE_VDSO)
48
49CFLAGS_vgettimeofday.o = $(CC_FLAGS_ADD_VDSO)
50CFLAGS_vgetrandom.o = $(CC_FLAGS_ADD_VDSO)
51
52ifneq ($(c-gettimeofday-y),)
53 CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
54endif
55
56ifneq ($(c-getrandom-y),)
57 CFLAGS_vgetrandom.o += -include $(c-getrandom-y)
58endif
59
60targets += vdso.lds
61CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
62
63# Link rule for the .so file, .lds has to be first
64$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
65 $(call if_changed,vdsold_and_vdso_check)
66
67# Strip rule for the .so file
68$(obj)/%.so: OBJCOPYFLAGS := -S
69$(obj)/%.so: $(obj)/%.so.dbg FORCE
70 $(call if_changed,objcopy)
71
72# Generate VDSO offsets using helper script
73gen-vdsosym := $(src)/gen_vdso_offsets.sh
74quiet_cmd_vdsosym = VDSOSYM $@
75 cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
76
77include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
78 $(call if_changed,vdsosym)
79
80# Actual build commands
81quiet_cmd_vdsold_and_vdso_check = LD $@
82 cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)